1. Field
The present embodiments relate to batteries for portable electronic devices. More specifically, the present embodiments relate to techniques for managing swelling in batteries for portable electronic devices.
2. Related Art
Portable electronic devices, such as laptop computers, portable media players, and/or mobile phones, typically operate using a rechargeable battery. Furthermore, designs for such batteries often include battery packs that contain battery cells connected together in various series and parallel configurations. For example, a six-cell battery pack of lithium cells may be configured in a three in series, two in parallel (3s2p) configuration. Hence, if a single cell can provide a maximum of 3 amps with a voltage ranging from 2.7 volts to 4.2 volts, then the entire battery pack can have a voltage range of 8.1 volts to 12.6 volts and provide 6 amps of current. The charge in such batteries is typically managed by a circuit, which is commonly known as a protection circuit module (PCM) and/or battery management unit (BMU).
During operation, the battery's capacity may diminish over time from use, age, lack of maintenance, damage, heat, and/or manufacturing defects. For example, oxidation of electrolyte and/or degradation of cathode and anode material within a battery may be caused by repeated charge cycles and/or age, which in turn may cause a gradual reduction in the battery's capacity. As the battery continues to age and degrade, the capacity's rate of reduction may increase. Moreover, once the battery reaches 80% of initial capacity, the battery's useful life may be finished.
Subsequent use of a battery beyond the battery's end-of-life may cause swelling of the battery's cells and may potentially damage the device that is powered by the battery, while providing little power to the device. Moreover, conventional battery-monitoring mechanisms may not include functionality to manage swelling of the battery. As a result, a user of the device may not be aware of the battery's swelling and/or degradation until the swelling results in damage to the device, which can possibly involve a fire and/or an explosion.
Hence, what is needed is a mechanism for managing and mitigating swelling in batteries for portable electronic devices.